Abstract
Proper myelination is required for effective neural circuit. Multiple organizations (for example, nodal clustering of ion channels, node of Ranvier formation and myelin compaction) advance myelination sequentially. However little is known about the effect of each factor on the increase in axonal conduction velocity (CV). In order to evaluate it, we developed a neuron-oligodendrocyte (OL) co-culture device. The culture device has microelectrodes-embedded microchannels by which propagating action potentials along axons are able to be recorded. Microchannels have OL culture areas between electrodes. Neurons and OL from rat cerebral cortex were cultured in the device. Although no myelin sheath was observed in microchannels, axonal conduction delay was significantly less in OL co-culture than that in culture without OL at 45 days in vitro. The difference is probably due to the OL-regulated clustering of voltage dependent sodium channels along axons. These results suggest that changes in CV that is caused by non-myelinating OL are detectable by the device. Then, this device is available for evaluating the contribution of individual factors to axonal conduction during myelination.
